Method for snap ring forming and grooving

ABSTRACT

A method for simultaneously forming splines and an annular groove in a metal piece having a central portion and ends on each side thereof, the method including the steps of forming a substantially U-shaped annular recess (56) along the central portion of the workpiece which has a flat base and spaced sidewalls which are spaced apart to a greater distance than the side walls of the groove (82) to be formed, deforming the recess (56) to initially form a groove (82) therein, progressively and simultaneously forming splines in the ends of the workpiece and forming the groove (82) in the recess of the workpiece, and moving metal outwardly and upwardly from the recess as the groove (82) is formed to fill the remainder of the recess (56) and form the sidewalls of the groove (82).

This application is a divisional application of U.S. Ser. No. 769,581,filed Aug. 25, 1985, now U.S. Pat. No. 4,644,772, issued on Feb. 24,1987.

TECHNICAL FIELD

The invention relates generally to a machine for forming splines and asnap ring groove in a cylindrical member.

BACKGROUND OF THE INVENTION

Mechanisms of the type for performing a splining operation on aworkpiece generally include a pair of elongated dies slidably mountedwith respect to each other and spaced in parallel relationship andmovable between an end-to-end relationship and an overlappingrelationship. Each of the dies include teeth spaced along the lengththereof for forming splines. Problems have been encountered in formingsnap ring grooves in cylindrically splined members and prior art methodshave employed grinding or other techniques for forming the grooves, forexample, cutting the grooves in after the splining operation which isexpensive and not economical on a mass production scale.

U.S. Pat. No. 446,932 to Simonds shows a method and apparatus for makingscrew threaded rolled formings including a groove forming section andthread forming protrusion and U.S. Pat. No. 446,933, also to Simonds,discloses a device for knurling the surface of metal articles includinga groove forming portion and a knurling forming portion. Another U.S.Pat. No. 446,934 to Simonds discloses a rolled forging making assemblyfor making non-circular members including spreading and reducingsurfaces and forming surfaces. However, none of the above patentsdisclose a mechanism for forming grooves in a splined member during asingle rolling operation.

STATEMENT OF INVENTION AND ADVANTAGES

The present invention is directed to a machine and method for forming asnap ring groove in a splined workpiece, as well as the resultant memberproduced thereby. The machine comprises mounting means rotatablysupporting the workpiece for rotary movement, die means includingopposed splineforming work surfaces spaced on opposite sides of the axisof the workpiece for forming splines therein, and is characterized bycutting means disposed in the work surfaces for grooving the workpieceas the work surfaces are moved relative to one another during thespline-forming operation.

The method comprises the steps of rotatably supporting the workpiece forrotary movement and movably supporting a plurality of die means havingspaced spline-forming work surfaces for movement relative to one anotheron opposite sides of the axis of the workpiece. The method ischaracterized by the steps of retaining a cutting member in thespline-forming work surfaces and moving the die means relative to oneanother to engage the spline-forming work surfaces and the cuttingmember with the workpiece therebetween, simultaneously performing agrooving and splining operation on the workpiece.

The resultant product is a transmission member having a splined portioncharacterized by a transverse groove formed therein by theabovedescribed process incorporating die means having opposingspline-forming work surfaces spaced for relative movement on oppositesides of a workpiece and cutting means disposed in the work surfaces forsimultaneously grooving the workpiece as the work surfaces arerelatively moved to form splines therein.

An advantage of the subject invention is simultaneous cold forming ofsplines and a snap ring groove in a workpiece with a single pass ofcold-forming dies.

Another advantage of the subject invention is that a shaft can befabricated having a snap ring groove formed in the splined portion witha minimal amount of burrs at the junction between the snap ring grooveand spline.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a perspective view showing a machine of the subject invention;

FIG. 2 is a perspective view of the invention prior to commencement ofthe forming operation;

FIG. 3 is an enlarged fragmentary cross-sectional view of the inventionprior to commencement of the groove-forming operation on the workpiece;

FIG. 4 is an enlarged fragmentary cross-sectional view of the inventionshowing the member being splined following commencement of thegroove-forming operation;

FIG. 5 is an enlarged fragmentary cross-sectional view of the inventionshowing the workpiece being splined as the groove is further beingformed in the workpiece;

FIG. 6 is an enlarged fragmentary cross-sectional view of the inventionshowing the final stage of the groove forming in the workpiece;

FIG. 7 is a cross-sectional view of the invention taken substantiallyalong the lines 7--7 of FIG. 5 showing a portion of the member beingsplined by one of the leading die teeth;

FIG. 8 is a cross-sectional view of the invention taken substantiallyalong the lines 8--8 of FIG. 6 showing a workpiece being splined by alarger one of the die teeth near the trailing edge of one of the dies;

FIG. 9 is a perspective view of the invention showing the resultantsplined member having a groove formed therein;

FIG. 10 is an enlarged fragmentary view of the invention showing analternative construction of one of the dies;

FIG. 11 is a perspective view of the invention showing a workpiece beinggrooved by opposed rotary dies during a spline-forming operation; and

FIG. 12 is a cross-sectional view of the invention taken substantiallyalong the lines 12--12 of FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1 a spline-forming machine adapted to form grooves in aworkpiece is generally shown at 10. The machine 10 includes a lowersupport base 12, an upper base 14, and a support portion 16. The supportportion 16 extends upwardly from the lower base 12 and the upper base 14extends forwardly from the support portion 16 to cooperate with thelower base in defining a downwardly Within the work space 18, a fixedhead stock 20 is mounted on the support portion 16 between the lower andupper bases 12 and 14. A tail stock support arm 22 projects downwardlyfrom the upper base 14 and includes a suitable slide arrangement forsupporting a tail stock or shaft 24 which is slidably movable toward andaway from the head stock 20 along a rectilinear path. The head stock 20includes a chuck member 26 having jaws 28 (shown diagrammatically inFIGS. 2 and 11) for retaining an end 30 of the workpiece, generallyindicated at 32, therein. The tail stock shaft 24 has a pointed end 34for centering the axis of the shaft 24 in a corresponding recess 36 inthe end of the workpiece 32 opposite the end 30 thereof held in thechuck member 26. The chuck member 26 and tail stock shaft 24, includingthe pointed end 34 received within the central recess 36 of an end ofthe workpiece 32, all comprise mounting means rotatably supporting theworkpiece for rotary movement. A pair of die means, shown in FIG. 1 aslower and upper die members, respectively, are generally indicated at 38and 40. The lower die member 38, shown in FIG. 1 as an elongated rack,is slidably supported on the lower base 12 by a slide support 42. Theupper die member 40 is also shown as an elongated rack slidablysupported on the upper base 14 by another slide support 44. The slidesupports 42 and 44 mount the dies 38 and 40 in a parallel spacedrelationship with respect to each other for sliding movement between anend-to-end relationship shown in FIG. 1 and indicated by the arrows, andan overlapping relationship. Each of the dies 38 and 40 is elongatedrectilinearly and has a spline-forming work surface comprising a seriesof teeth, generally indicated at 46, spaced along the length thereof.The die teeth 46 on each work surface extend transversely with respectto the direction of die movement and are oriented in a spaced andparallel fashion opposing the die teeth of the other of said die memberswhen the dies assume their overlapping relationship after movement inthe direction of the arrows 48 as shown in FIG. 1. The dies are actuatedby a suitable power-operated actuator that coordinates the movement ofeach die with that of the other to perform the splining operation of thesubject invention. Suitable deflection control means are associated withthe respective bases to control the deflection permitted between thedies as the splining operation proceeds. According to the invention,there is provided cutting means, in the form of a blade member 48,disposed in each of said work surfaces 46 for grooving the workpiece 32as said work surfaces 46 are moved relative to one another during thespline-forming operation.

As shown more clearly in FIG. 2, the die member 38 comprises separateelongated body portions 50,52 having dual upper work surfaces 46 securedtogether by bolts 54 and separated by the cutting member 48 beingsandwiched therebetween, forming a unitary composite structure.

The mounting means hereinbefore described rotatably supports a generallycylindrical workpiece 32 between the opposed work surfaces 46 which areshown in FIG. 2 prior to the commencement of the respective formingoperations. According to the invention, the workpiece 32 is preformedwith a recess 56 adapted to cooperate with the blade member 48,resulting in a vertically walled snap ring groove described below inconjunction with FIGS. 3 through 6. Each blade member 48 is identical inconfiguration and has opposed leading 58 and trailing 60 edgesrespectively situated adjacent leading 62 and trailing 64 end teeth ofsaid work surfaces 46. The blade member 48 has a rounded exposed edge atthe leading edge 58 thereof and tapers along the length of the blademember to a squared cross section at the trailing edge 60.Alternatively, the blade member 48 may have a pointed exposed leadingedge 58 tapering to a rectangular cross section at said trailing edge60. Each blade member 48 preferably has a progressively increasingheight (at an angle indicated by the arrows in FIG. 2) from the leadingto the trailing edge thereof so that continued opposed movement of thedie members 38,40 progressively cuts a deeper groove into the recess 56of the workpiece 32. The work surfaces 46 on the respective bodyportions 50,52 of the dies 38,40 are grooved together with teeth on oneof said work surfaces 46 forming a continuation or extension of teeth onthe other of said work surfaces, that is, valleys between the die teethon one side of the blade member 48 are precisely continuous withcorresponding valleys on the other side of said blade member 48 forsynchronous forming by the dual work surfaces. Preferably, each of thebody portions 50,52 have corresponding nontoothed surfaces 66 situatedon either side of the blade member adjacent the leading edge 58 thereof,allowing initial grooving of the workpiece 32 at the leading edge priorto commencement of a simultaneous splining operation.

FIG. 10 shows an alternative construction of a portion of a die memberhaving a solid one-piece body portion 68 formed with an elongated slot70 extending transversely to the work surfaces 46 for receiving andretaining the blade member 48 therein. It is also possible to constructa die member wherein a groove-forming blade extends discontinuously froma leading to a trailing end of the toothed work surface, forming groovesin the workpiece only adjacent the leading and trailing edges of theblade member without the necessity for an intermediate forming portionof the blade.

As shown in FIGS. 7 and 8, the teeth on the spline-forming surfaces 46of the dies have progressively increasing heights from the leading end62 to the trailing end 64 thereof to progressively form splines in theworkpiece as the dies members 38,40 are moved from an end-to-endrelationship to an overlapping relationship. Thus, both the splines andgrooves are progressively formed as illustrated in FIGS. 3 through 8.

In FIG. 3, the rounded leading edge 58 of the blade member is shownprior to contact with the bottom of the recess 50 (shown for referencepurposes as a phantom line 50 in FIGS. 4 through 8). The squaredtrailing edge 60 of the blade 48 is shown by phantom lines 60 in FIGS. 3through 5.

FIG. 3 shows the exposed leading edge 58 of the blade member 48extending outwardly from the leading end 62 (FIGS. 1, 2 and 10) in thedirection of movement of its associated die member, prior to contactwith the recess 50 in the workpiece 32. The level of the untoothedsurface 66 preceding the leading teeth 74 of the work surface 46 (FIG.2) represents the root 74 of the teeth on spline-forming surfaces 46.

The method for performing a spline-forming operation on the workpiece 32comprises the steps of rotatably supporting the workpiece 32 for rotarymovement utilizing the aforesaid mounting means; movably supporting thedie members 38,40 having spaced spline-forming work surfaces 46 formovement relative to one another on opposite sides of the axis of theworkpiece 32 and retaining the cutting member 48 therein. FIG. 4illustrates the subsequent step of moving the die members relative toone another to engage initially the leading teeth 62 on the respectivespline-forming surfaces 46 and said cutting members 48 with theworkpiece 32 therebetween. The crest 72 of one of the leading teeth 62is shown in FIG. 4 forming a spline 76 in the outer wall 78 of theworkpiece 32. As the leading edge 58 of the cutting member 48 begins todeform the bottom of the recess 50, the metal is moved outwardly andupwardly to fill the recess 50 while defining side walls 80 of a snapring groove 82.

In FIG. 5, the die members have been further moved relative to oneanother to engage an intermediate tapered portion 84 of the blade member48 to further deform the groove 82, causing migration of more materialinto the recess 50 to further define vertical side walls 80 of thegroove 82. The intermediate edge 84 of the blade 48 is rectangular withrounded corners to progressively form the bottom of the snap ring groove82 into a squared configuration. The dotted reference line 50 indicatesthe original position of the recess in the area of material which iscaused to migrate during the forming of the groove 82.

In FIG. 6, the die members have been moved from an end-to-endrelationship all the way to an overlapping relationship to engage teethon the respective trailing edges of the dies and the squared trailingedge 60 of the blade member 48 with the workpiece 32 therebetween tofinish forming the groove 82 therein.

FIG. 6 depicts the completed grooving operation following movement ofthe dies from their end-to-end relationship to their overlappingrelationship. The trailing edge 60 of the blade member 48 is shown bysolid lines in the position shown in phantom in FIGS. 3 through 5.

FIG. 7 illustrates the progressive splineforming operation by teethhaving progressively increasing heights from the leading 62 to thetrailing 64 ends of the respective work surfaces 46. The representativetooth shown in FIG. 7 is situated adjacent the intermediate tapered edgeof the blade member and the root 74 thereof is spaced from the outersurface 78 of the workpiece.

As the groove 82 is being formed and material of the preformed recess 56moved to fill the recess 56, the original outer surface 78 of theworkpiece, shown in solid lines in FIGS. 3 through 5, is deformed by thedie teeth 62,64 during the simultaneous spline-forming operation. Thedie teeth 62,64 deform the outer surface 78 of the workpiece, formingsplines 76 each having a root 86 (FIGS. 7, 8 and 9) and a crestrepresented by the outer splined surface 78 of the workpiece. The outersurface 78 is deformed so that metal is displaced above and below theoriginal unsplined surface 78 of the workpiece, respectively forming thecrest 88 and the root 86 of each of the splines 76. This displacement ofmetal is combined with the displacement occurring vis-a-vis thesimultaneous grooving operation taking place during the spliningoperation, particularly, filling of the original preformed groove 50(solid lines in FIG. 3) by the material displaced by the cutting blade48, causing a further build-up of the outer surface of the workpiece.

FIG. 6 illustrates the actual displacement of the original outer surface78 (shown in phantom) of the workpiece so that the crest 88 of eachspline 76 abuts the root 74 of each die tooth 64 and the root 86 of eachspline is contiguous with the crest 72 of the die tooth 64 during thespline-forming operation. In further reference to FIG. 6, the areabounded by phantom line 78 (original outer surface of the workpiece) andthe crest 88 of the spline 76 (shown in brackets) represents thematerial which has been displaced upwardly from the original outersurface 78 (phantom) of the workpiece. Similarly, the area bounded bythe root 86 (shown in phantom) and the original outer surface 78 (shownin phantom) represents the valley displaced to form the splines 76 inthe workpiece. It will be further noted that additional material isdisplaced by the blade member 48, as described above, completely fillsin the recess and rises around the blade member 48 during the formingoperations until it is contiguous with the completely formed splines asshown in FIG. 6.

In summary, a member resulting from the above-described operationsperformed on a workpiece 32, as depicted in FIG. 9, has a splinedportion including splines 76 and a circumferentially extending groove 82formed in said splined portion by a process incorporating the aboveplurality of die members having opposing spline-forming work surfaces 46spaced for relative movement on opposite sides of the workpiece 32 and acutting member 48 disposed in said work surfaces 46 for simultaneouslygrooving the workpiece 32 as said work surfaces 46 are relatively movedto form splines 76 in the workpiece 32. The preformed recess 50 in theworkpiece 32 is deformed into a finished groove 82 having vertical sidewalls 80 by successively engaging rounded leading edges 58 of opposedcutting members 48 with said workpiece 32 and thence an intermediatetapering to a squared trailing edge 60 to progressively form a snap ringgroove 80 having a generally flat bottom to receive the circumferentialedge of a cup-shaped member or the like.

An alternative die configuration is shown in FIGS. 11 and 12, wherein apair of rotary die means, generally indicated at 90 and 92,respectively, comprise opposed curvilinear toothed work surfaces 46mounted for relative rotary movement. An end 30 of the workpiece 32 isrotatably supported within the jaws 28 of a chuck member (not shown)similar to the manner described above and a tail stock supported on asupport arm 22 for movement toward and away from the chuck member has acentering point 34 adapted to be received within the recess 36 at theopposite end of the workpiece 32. The die members 90,92 are shownwithout their associated support structures which are constructed inaccordance with a manner well-known in the art. Each of the dies 90,92typically has an unsplined shaft portion 94 extending toward the tailstock support arm 22 and having a row of circumferentially extendingteeth 96 engaging a similar row of circumferentially extending teeth 98on said tail stock 24. The die members are rotated by a suitable drivemeans (not shown) so that opposing pairs of teeth 96,98 on the shaftmember 94 and tail stock 24, respectively, are engaged to drive the diesduring the forming operations. Either of the dies 90 or 92 can be thedriven die.

FIG. 12 diagrammatically shows the arrangement of teeth on the dual worksurfaces 46 of the dies 90,92 with the teeth circumferentially extendingabout the rotary dies 90,92 from a leading edge 62 to a trailing edge64, whereby the dies are rotated to engage opposing teeth on the leadingend 62 of the respective work surfaces of the dies along with theleading edges 58 of the cutting member 48 during commencement of theforming operations. The upper die 90 is rotated counterclockwise and thelower die 92 rotated counterclockwise (arrows) forming splines and agroove as the workpiece rotates, until the dies are ultimately rotatedto engage teeth on the trailing end 64 of the work surfaces 46 and thetrailing edge 60 of the blade members 48, completely forming splines 76and a groove 82 in the workpiece 32. The dies are then returned to theinitial position. To facilitate loading and unloading of the workpiecefrom between the dies, notch portions 100 are provided in each die andaligned together in the loading position to accommodate loading of theworkpiece between the dies and unloading of the workpiece following theoperation.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology which has been used is intended to bein the nature of words of description rather than of limitation.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. It is, therefore, to beunderstood that within the scope of the appended claims whereinreference numerals are merely for convenience and are not to be in anyway limiting, the invention may be practiced otherwise than asspecifically described.

What is claimed is:
 1. A method for simultaneously forming splines andan annular groove in a metal workpiece having central portions and endson each side thereof, said method including the steps of: forming asubstantially U-shaped annular recess (56) along the central portion ofthe workpiece which has a flat base and spaced side walls which arespaced apart to a greater distance than the side walls of the groove(82) to be formed; deforming the recess (56) to initially form a groove(82) therein; progressively and simultaneously forming splines in theends of the workpiece and forming the groove (82) in the recess of theworkpiece and moving metal outwardly and upwardly from the recess as thegroove (82) is formed to fill the remainder of the recess (56) and formthe side walls of the groove (82).
 2. A method as set forth in claim 1wherein said step of forming the recess (56) is further defined asoutwardly angling the side walls of the recess (56).
 3. A method as setforth in claim 31 further characterized by the steps of deforming therecess (56) by engaging a leading edge (58) of an elongated blade member(48) with said recess (56) and forming the groove (82) therein prior toengaging opposed teeth at respective leading ends (62) of spline-formingwork surfaces (46) with the outer surface of workpiece (32);subsequently engaging a trailing edge (60) of the blade member (48) withsaid recess (56) after a trailing end (64) of said spline-formingsurface (46) has disengaged the workpiece (32).
 4. A method as set forthin claim 3 further characterized by:continuously performing a groovingoperation on the workpiece while said work surfaces (46) are beingrelatively moved on opposite sides thereof.
 5. A method as set forth inclaim 3 further characterized by the steps of:preforming a recess (56)in said workpiece (32); relatively moving said blade members (48) toengage the bottom of said recess (56), causing material in said recess(56) to migrate forming a vertically walled (80) groove (82).
 6. Amethod as set forth in claim 3 further characterized by successivelyengaging rounded leading edges (58) of opposed blade member (48) withsaid recess, then intermediate tapering edges and finally a tapering toa squared trailing edge (6) thereof, progressively forming the groove(82) in said recess (56).